How is it possible for an organization, with the same resources, to generate 50% more throughput or…

How is it possible for an organization, with the same resources, to generate 50% more throughput or to reduce project cycle time (duration) by more than 20%?.
If you begin to measure the number of project tasks completed each week, and a task that you measured as complete last week now needs rework, how should this be counted in a data report? What behavior are you trying to encourage by these data, for resources and for the people managing the resources and tasks?
An increase in throughput could be a result of many different things in an organization, other than project management improvement. Is it worthwhile trying to distinguish between the throughput increase that comes from other sources and that which comes from multi-project management improvement?